Add test case for context click at misspelled word boundary

third_party/WebKit/LayoutTests/editing/spelling/context_click_select_misspelling.html

Index: third_party/WebKit/LayoutTests/editing/spelling/context_click_select_misspelling.html
diff --git a/third_party/WebKit/LayoutTests/editing/spelling/context_click_select_misspelling.html b/third_party/WebKit/LayoutTests/editing/spelling/context_click_select_misspelling.html
index 199edbf4808fbb5b41bc145a689391624ffbbac5..a29f25baaeb2bb2c8434cd44635957f5aee7d9c7 100644
--- a/third_party/WebKit/LayoutTests/editing/spelling/context_click_select_misspelling.html
+++ b/third_party/WebKit/LayoutTests/editing/spelling/context_click_select_misspelling.html
@@ -11,7 +11,7 @@ test(() => assert_not_equals(window.internals, undefined),
 test(() => assert_not_equals(window.eventSender, undefined),
      'This test requires event sender to simulate keyboard and mouse actions.');
 
-const kNumTests = 4;
+const kNumTests = 5;
 const heldTest = async_test(
     () => assert_true(true),
     'Dummy async test for blocking test harness.',
@@ -94,6 +94,36 @@ spellcheck_test(
     '',
     '<div contenteditable>#wellcome# home.</div>',
     {
+      title: 'Context click at boundary of misspelled word.',

[Xiaocheng, 2017/06/10 01:02:51]

nit: The title should be "Setup of context clicking at boundary of a misspelled
word".

+      callback: sample => test(() => {
+        const container = sample.document.querySelector('div');
+        const shouldSelect = isMac(navigator.platform);
+
+        assertContextClickSelection(
+            container, 0, '',

[rlanday, 2017/06/10 00:40:05]

Note: we might want to modify this test so the misspelled word isn't at the
start of the range; right-clicking immediately before a misspelled word selects
it on Mac, but when the test runs, nothing is getting selected. I this is
because clicking right on the boundary of some editable text is treated
differently than clicking in the interior of the text.

[Xiaocheng, 2017/06/10 01:02:51]

If the behavior on Mac is different when the misspelled word is not at the
beginning, could you add another test case for it, so that the current behavior
is covered as much as possible?

[Xiaocheng, 2017/06/10 01:07:30]

Wait... Let's investigate first why the behavior in layout test is different
from real Chrome.

We should eliminate such cases.

+            'Context clicking immediately before "wellcome" does not select it');
+
+        // On Mac, right-clicking immediately after a word will select the space after it.
+        if (shouldSelect) {
+          assertContextClickSelection(
+            container, 8, ' ',
+            'Context clicking immediately after "wellcome" selects the space after it');
+          return;
+        }
+
+        assertContextClickSelection(
+            container, 8, '',
+            'Context clicking immediately after "wellcome" does not select it');
+      },
+      'Context clicking immediately before or after misspelled word in editable DIV does not select it.',
+      {sample: sample, blockHeldTest: true})
+    });
+
+spellcheck_test(
+    '<div contenteditable>wellcome home.|</div>',
+    '',
+    '<div contenteditable>#wellcome# home.</div>',
+    {
       title: 'Mark initial misspelling "wellcome" in editable DIV.',
       callback: sample => test(() => {
         const container = sample.document.querySelector('div');